This invention relates to a method and apparatus for spraying grout onto the interior surface of an enclosed elongated cavity. By "spraying" is meant that the material is impelled or thrown onto the surface of the cavity. The invention has particular applicability for use in spraying first a washing fluid and then an uncured grout material onto the interior surfaces of manholes to be repaired. The invention also has application for the washing and grouting of the interior surfaces of elongated cavities having cylindrical, cone shaped, or other shaped surfaces.
One presently known method of repairing existing manholes is the placement of a coating of a cementatious grout onto the interior surface of the manhole wall. The grout is applied in an uncured state and is permitted to cure.
Presently known methods for applying the grout include the troweling of the grout onto the walls of the manhole and/or spraying the grout onto the wall of the manhole. In both of these cases it is necessary for the person applying the grout to enter into the manhole for either troweling or spraying the grout onto the walls. When the spraying method is used, a final troweling step usually is required in order to obtain the desired compaction, surface and thickness for the grout material.
One disadvantage of presently known methods for coating the interior surfaces of manholes with grout is the difficulty in obtaining a uniform thickness to the grout throughout the entire manhole. This can only be achieved by providing random measurements of the grouting or by providing lands extending radially inwardly from the manhole wall to show the desired thickness. When lands are used, they ultimately are embedded within the grout after the grout has been applied, and tend to weaken the grout and reduce its waterproofing characteristics.
Therefore, a primary object of the present invention is the provision of an improved method and apparatus for spraying grout onto the interior surface of an enclosed elongated cavity.
A further object of the present invention is the provision of a method and apparatus for spraying grout onto the interior of an enclosed elongated cavity which eliminates the need for the operator to enter into the cavity to accomplish the spraying.
A further object of the present invention is the provision of an improved method and apparatus for spraying grout onto the interior surface of an elongated cavity wherein a uniform thickness of grout may be applied over the entire wall of the enclosed elongated cavity.
A further object of the present invention is the provision of an improved method and apparatus for spraying grout onto the interior surface of an elongated cavity wherein the amount of grout may be carefully metered to determine the desired thickness of the grout on the cavity wall.
A further object of the present invention is the provision of an improved method and apparatus for spraying grout onto the interior surface of an elongated cavity which permits uniform application of grout around projections extending inwardly from the walls of the cavity.
A further object of the present invention is the provision of an improved method and apparatus for spraying grout onto the interior surface of an elongated cavity which propels the grout against the walls of the cavity in a circular pattern, and which permits the reversal of the rotational direction at which the grout is propelled against the walls of the cavity.
A further object of the present invention is the provision of an improved method and apparatus for spraying onto the interior surface of an elongated cavity which is efficient in operation, economical in manufacture, and durable in use.